Imaging devices, such as cameras, can be used to capture images of portions of the electromagnetic spectrum, such as the visible light spectrum, incident upon an image sensor. For ease of discussion, the term light is generically used to cover radiation across the entire electromagnetic spectrum. In a typical imaging device, light enters through an opening (aperture) at one end of the imaging device and is directed to an image sensor by one or more optical elements such as lenses. The image sensor includes pixels or sensor elements that generate signals upon receiving light via the optical element. Commonly used image sensors include charge-coupled device (CCDs) sensors and complementary metal-oxide semiconductor (CMOS) sensors.
Generally, image capture utilizes a single image sensor, to capture individual images, one at a time. A digital camera typically combines both an image sensor and processing capabilities. When the digital camera takes a photograph, the data captured by the image sensor is provided to the processor by the image sensor. Processors are able to control aspects of a captured image by changing image capture parameters of the sensor elements or groups of sensor elements used to capture the image. Integration time, which is the length of time that a sensor element measures incident light, is one parameter that can be adjusted to increase or decrease light exposure for an image sensor. Another parameter that the processor can control is pixel gain, which is the adjustment of the scaling applied to the signal generated by the sensor element.